Recently, the 3D printing, also known as the additive manufacturing (or called “AM”), is more and more general, among which the digital light processing (hereinafter “DLP”) additive manufacturing is widely applied to kinds of machines. The DLP additive manufacturing is applying projection technology to project layered images of objects on photopolymer in sequence, and the layers are stacked for molding.
Since the resolution and molding velocity of the products in the DLP additive manufacturing are relevant to the projection light source, the projection area of conventional machines is narrowed to a specific range for ensuring the resolution and the optical power in a unit area, such that the object can be molded successfully. Consequently, although the accuracy, resolution and velocity of the DLP additive manufacturing are superior to other additive manufacturing methods, the DLP additive manufacturing is unable to be applied to large objects because the projection range cannot be expanded.
In prior arts, projection images with large area are divided into several sub-images. By moving the projection light source and composing the sub-images, a larger projection area can be obtained, such that the molding range of the DLP additive manufacturing is expanded. However, since the the projection light source is large and heavy, the velocity and accuracy of moving the projection light source are low, and the velocity and accuracy of molding are further affected. In addition, errors of the composing of images are caused easily because of the moving inertia and vibration of the projection light source, such that the molding quality is lowered.
Therefore, there is a need of providing an exposure molding device and an exposure molding method thereof to solve the drawbacks in prior arts, expand the molding range, and achieve the advantages of enhancing the accuracy, velocity and quality of molding.